What would the entries be in columns 7a and 14 when visibility is observed to be varying rapidly between 1 5/8 and 2 1/4 miles?

When visibility is reported as rapidly varying between two measurements, the standard procedure for documenting this in aviation weather observations is to determine a mean value for column 7a and to represent the range of visibility in column 14.

In this case, the visibility is fluctuating between 1 5/8 miles and 2 1/4 miles. The mean visibility value is found by averaging these two measurements. The mid-point between 1 5/8 (which is 1.625 miles) and 2 1/4 (which is 2.25 miles) is calculated as follows:

• Convert both measurements to a decimal for easier calculation.

• 1 5/8 is 1.625, and 2 1/4 is 2.25.

• The average (mean) visibility can be calculated by adding both values and dividing by 2:

(1.625 + 2.25) / 2 = 3.875 / 2 = 1.9375.

• This value translates back to 1 7/8 miles when expressed in the appropriate fraction for column 7a.

For column 14, the visibility needs to represent the rapidly varying conditions, so it